A method of processing by controlling one or more beam characteristics of an optical beam may include: launching the optical beam into a first length of fiber having a first refractive-index profile (RIP); coupling the optical beam from the first length of fiber into a second length of fiber having a second RIP and one or more confinement regions; modifying the one or more beam characteristics of the optical beam in the first length of fiber, in the second length of fiber, or in the first and second lengths of fiber; confining the modified one or more beam characteristics of the optical beam within the one or more confinement regions of the second length of fiber; and/or generating an output beam, having the modified one or more beam characteristics of the optical beam, from the second length of fiber. The first RIP may differ from the second RIP.

The technology disclosed relates to high utilization of donor material in a writing process using Laser-Induced Forward Transfer. Specifically, the technology relates to reusing, or recycling, unused donor material by recoating target substrates with donor material after a writing process is performed with the target substrate. Further, the technology relates to target substrates including a pattern of discrete separated dots to be individually ejected from the target substrate using LIFT.

The technology disclosed relates to high utilization of donor material in a writing process using Laser-Induced Forward Transfer. Specifically, the technology relates to reusing, or recycling, unused donor material by recoating target substrates with donor material after a writing process is performed with the target substrate. Further, the technology relates to target substrates including a pattern of discrete separated dots to be individually ejected from the target substrate using LIFT.

A laser processing apparatus is used which includes: a laser oscillator that oscillates a processing laser beam at a processing point to be processed on a surface of a workpiece; an optical interferometer that emits a measurement beam to the processing point and generates an optical interference intensity signal based on interference generated due to an optical path difference between the measurement beam reflected at the processing point and a reference beam; a first mirror that changes traveling directions of the processing laser beam and the measurement beam; a second mirror that changes an incident angle of the measurement beam onto the first mirror; a lens that focuses the processing laser beam and the measurement beam on the processing point; a memory that stores corrected processing data; a control unit that controls the laser oscillator, the first mirror, and the second mirror based on the corrected processing data; and a measurement processing unit that derives a depth of a keyhole generated at the processing point by the processing laser beam, based on the optical interference intensity signal.

Disclosed herein are methods, apparatus, and systems for providing an optical beam delivery system, comprising an optical fiber including a first length of fiber comprising a first RIP formed to enable, at least in part, modification of one or more beam characteristics of an optical beam by a perturbation assembly arranged to modify the one or more beam characteristics, the perturbation assembly coupled to the first length of fiber or integral with the first length of fiber, or a combination thereof and a second length of fiber coupled to the first length of fiber and having a second RIP formed to preserve at least a portion of the one or more beam characteristics of the optical beam modified by the perturbation assembly within one or more first confinement regions. The optical beam delivery system may include an optical system coupled to the second length of fiber including one or more free-space optics configured to receive and transmit an optical beam comprising the modified one or more beam characteristics.

A method of processing by controlling one or more beam characteristics of an optical beam may include: launching the optical beam into a first length of fiber having a first refractive-index profile (RIP); coupling the optical beam from the first length of fiber into a second length of fiber having a second RIP and one or more confinement regions; modifying the one or more beam characteristics of the optical beam in the first length of fiber, in the second length of fiber, or in the first and second lengths of fiber; confining the modified one or more beam characteristics of the optical beam within the one or more confinement regions of the second length of fiber; and/or generating an output beam, having the modified one or more beam characteristics of the optical beam, from the second length of fiber. The first RIP may differ from the second RIP.

A method of processing by controlling one or more beam characteristics of an optical beam may include: launching the optical beam into a first length of fiber having a first refractive-index profile (RIP); coupling the optical beam from the first length of fiber into a second length of fiber having a second RIP and one or more confinement regions; modifying the one or more beam characteristics of the optical beam in the first length of fiber, in the second length of fiber, or in the first and second lengths of fiber; confining the modified one or more beam characteristics of the optical beam within the one or more confinement regions of the second length of fiber; and/or generating an output beam, having the modified one or more beam characteristics of the optical beam, from the second length of fiber. The first RIP may differ from the second RIP.

In a case where a variation in reflection resistance among fiber lasers occurs, a reflection resistance of a fiber laser system as a whole is restored by reducing the variation while maintaining an output power of the fiber laser system as a whole. The fiber laser system includes a control section (C) configured to increase a proportion of a backward excitation power (PBi) in a fiber laser (FLi) so that fiber lasers (FL1 through FLn) less vary in reflection resistance.

A laser processing method includes a first step of irradiating a surface of a composite material with laser to form a hole processing groove on the composite material in a manner of scanning paths from an outside corresponding to an inner peripheral surface side of the through hole to be formed to an inside corresponding to a center side of the through hole, the paths being across a width direction of the hole processing groove; and a second step of irradiating and penetrating through the hole processing groove with the laser to form the through hole in a manner of scanning paths from the outside to the inside after the first step, the paths being across the width direction of the hole processing groove. The laser used at the first step has a smaller heat input amount per unit time than the laser used at the second step.

A laser processing method includes a first step of irradiating a surface of a composite material with laser to form a hole processing groove on the composite material in a manner of scanning paths from an outside corresponding to an inner peripheral surface side of the through hole to be formed to an inside corresponding to a center side of the through hole, the paths being across a width direction of the hole processing groove; and a second step of irradiating and penetrating through the hole processing groove with the laser to form the through hole in a manner of scanning paths from the outside to the inside after the first step, the paths being across the width direction of the hole processing groove. The laser used at the first step has a smaller heat input amount per unit time than the laser used at the second step.